Abstract: In order to study the effects of different planting densities on the yield and oil content of linseed（Linum usitatissimum L.）, this experiment employed a randomized complete block design under the saline-alkali condition（125°9’E, 46°34’N） of Daqing City, Heilongjiang Province, and linseed cultivars of Shuangyouma No.1, No.2 and No.3 were chosen as test materials; the planting densities were 3.5,6.0, 8.5, 11 million plants · hm^-2, and there were 12 treatments in total for this experiment. The results showed that planting density had no effect on the whole growth period, plant height, the height to the base of branch, number of branches, number of seeds per capsule and 1000-seed weight of the same linseed cultivar; with the increase of planting density, the stem diameter of the three linseed cultivars decreased gradually, the number of harvested plants increased gradually, the number of plant capsules decreased gradually, and the yield came to the highest value under the planting density of 6.0 million plants · hm^-2. There was no obvious difference of oil content change. In addition, the yields of three linseed cultivars were positively correlated with the number of harvested plants, and negatively correlated with the number of plant capsules. In summary, the results of yield and principal component analysis showed that Shuangyouma No.2 planted at the density of 6.0 million plants · hm^-2 was the best choice for high-yielding and high-quality in the test site. This study could provide scientific basis for the exploration of the optimal planting density of linseed in saline-alkali land of Heilongjiang Province, as well as the popularization and application of cultivars.